docs: update directory url in readme

Author: paodb

README.md

@@ -1,5 +1,5 @@
-[![Published on Vaadin Directory](https://img.shields.io/badge/Vaadin%20Directory-published-00b4f0.svg)](https://vaadin.com/directory/component/flip-card-addon)
-[![Stars on vaadin.com/directory](https://img.shields.io/vaadin-directory/star/flip-card--addon.svg)](https://vaadin.com/directory/component/flip-card-addon)
+[![Published on Vaadin Directory](https://img.shields.io/badge/Vaadin%20Directory-published-00b4f0.svg)](https://vaadin.com/directory/component/flip-card-add-on)
+[![Stars on vaadin.com/directory](https://img.shields.io/vaadin-directory/star/flip-card-add-on.svg)](https://vaadin.com/directory/component/flip-card-add-on)
 [![Build Status](https://jenkins.flowingcode.com/job/FlipCard-addon/badge/icon)](https://jenkins.flowingcode.com/job/FlipCard-addon)
 
 # Flip Card Add-on
@@ -30,7 +30,7 @@ The Flip Card Web Component includes CSS variables that help style the component
 
 ## Download release
 
-[Available in Vaadin Directory](https://vaadin.com/directory/component/flip-card-addon)
+[Available in Vaadin Directory](https://vaadin.com/directory/component/flip-card-add-on)
 
 ### Maven install